Water taps conventionally have a tap body including a valve seat, and a tap spindle which is able to be advanced or retraced relative to said tap body so u to advance a jumper washer into, or retract it from, engagement with the valve seat to respectively close and open the tap.
When the tap is closed, compression of the jumper valve prevents further rotation of the tap spindle in the tap closing direction. A locking device of some kind is provided to prevent continued rotation of the spindle in the tap opening direction. Generally an abutment of some kind is provided between a portion on the tap spindle and a portion on the tap body which prevents further rotation of the tap spindle.
Unfortunately many water taps in public places such as public lavatories, parks, and the like are subject to attack by vandals. In particular, vandals often turn the tap fully on and then, using both hands, apply a maximum possible opening torque to the tap handle. This generally results in either one of two eventualities. The first eventuality is that the tap spindle shears and the tap handle comes away thereby permanently damaging the tap and making it difficult for the flow of water from the open tap to be turned off subsequently by a lavatory attendant, park maintenance officer, or similar public official. This is the lesser of two evils since although the tap is turned fully on, at least the water is directed to flow out the spout of the tap.
The other eventuality is that the tap body is fabricated in two parts and the torque transmitted via the spindle to the upper part of the tap body is sufficient to cause the upper part of the tap body to rotate. Continued rotation in the tap opening direction is then sufficient to cause the upper part of the tap body to disengage from the valve seat. As a consequence, the entire upper part of the tap body is lost by being stolen by the vandal, and water under mains pressure shoots upwardly from the valve seat, thereby causing damage to ceilings, light fittings, and the like.
The object of the present invention is to provide a tap body and spindle arrangement which will substantially overcome, or at least ameliorate, the abovementioned vandal induced damage to conventional taps.
The present invention was covered accidentally as a result of the work done in placing the invention described in the specification of international patent application no PCT/AU97/00620 in the name of the present applicant, into practise. The entire contents of the abovementioned international patent application are hereby incorporated into the present specification by means of cross reference.
When the first off-tool samples of the tap described in the abovementioned international patent specification were received by the present applicant, it was noticed that because the material of the tap body and spindle, being predominantly plastics, was relatively soft, that item excessive turning of the tap spindle in the tap opening direction was sufficient to cause deformation of the moulded plastics components leading to permanent damage. This is essentially because the threaded engagement between the spindle and tap body provides a substantial mechanical advantage in converting rotational force applied to the tap spindle into a translational force extending in the direction of the axis of rotation of the tap spindle.
However, in relation to the embodiments of the tap illustrated in FIGS. 8 and 9 of the abovementioned international patent specification, and which are provided with a locking collar 62 or 72 which threadably engages with the tap body, in unusual circumstances a very unusual result was able to be achieved. These unusual circumstances were that (i) the locking collar was only just threadably engaged with the tap body, and (ii) instead of continuing to rotate the locking collar 62 or 72 so as to complete the assembly of the tap, (iii) the spindle 7 was then turned to a maximum extent in the tap opening direction, it was discovered that the threaded portions 18 and 19 disengaged and the spindle 7 freewheeled prior to causing any damage to either the spindle, the locking collar or the body. Only when this happenstance occurred, did the present invention come to be grasped and its significance be realised.